Windows XP VM only recognizes 3GB of RAM when given 4GB

[TheVMinator]

I'm having an issue with Windows XP only recognizing 3GB of RAM. XP 32-bit has a max RAM configuration of 4GB, (and can't be extended with PAE as some other versions can). The virtual machine in VMware is configured with 4GB of RAM. However, I can't get the OS to see more than 3GB. I had a somewhat similar issue with a Linux VM, which in that case was resolved by installing PAE. The odd thing in both cases was, that even though the limit is 4GB, if I set the VM RAM to 3.5, 3.8, or 3.9 GB of RAM, it would always show up in the guest OS as 3GB of RAM and no more.

Has anyone seen this issue or have any input? Thanks-

[FranckRookie]

Hi TheVMinator,

If I remember correctly, you need to add the "/PAE" switch in the Boot.ini file of your XP guest, at the end of your system boot device selection ( "multi(0)disk(0)rdisk(0)..." ).

Hope it helps.

Regards

Franck

[TheVMinator]

OK thanks - I tried adding that - no luck yet - still showing up as 3GB of RAM inside Windows when the VM is configured for 4GB.

[admin · Accepted solution]

You are probably seeing the PCI hole. See KB 1014006

[TheVMinator]

ok thanks - that looks like what is happening - also I found this helpful info

http://www.dansdata.com/askdan00015.htm

[jshrek]

I have a physical machine running Win XP Pro SP3 with 4GB installed, with /3GB switch in boot.init and when I click My Computer > Properties it shows 3.75GB og memory (which is correct because of PCI allocation).

I installed Win Xp Pro SP3 in Fusion v4 (MacBook Pro with 8GB installed RAM) and assigned 4096MB of RAM but properties only shows 3.00GB. I have tried the /3GB and /PAE switches in boot.ini as well but it does not change. If I change assigned RAM to 3072MB properties will still show 3.00GB as well. And yes, I shut down virtual machine before changing assigned ram and also reboot virtual machine after making boot.ini changes.

Thanks

[admin]

The PCI hole in your VM is probably 1GB.  See KB 1014006

[Tyomni]

This also happens due to VGA memory size. If it is more than 521mb and you have 4 GB more ram and running 32 bit OS, it may show only 3GB of it.

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